GB585330A - Improvements in or relating to turbines - Google Patents

Abstract

585,330. Gas turbines. GRIFFITH, A. A. April 8, 1941, No. 4699. [Classes 110 (i) and 110 (iii)] [Also in Group XXXIII] In a gas turbine of the type in which many discs, independently mounted and, it may be, oppositely rotating, carry both turbine and aircompressor bladings, some of the discs carry also airscrew blades. Discs 17 of the low pressure part of the gas turbine carry air compressor blades 20, gas turbine blades 22 and air-screw blades 24. The air-screw blades operate within an annular chamber 11 open up-stream and discharging at 12 over the surface of the supporting aeroplane wing 10. Air is taken from the chamber 11 by two chutes 37, the open ends of which are turned to face the stream, and is delivered to an annular inlet chamber 38 of the air-compressor. Air is delivered from the high-pressure compressor stage 25 to a combustion chamber 32 and the products of combustion pass rearwardly through the turbine blades and discharge into the chamber 11. The chamber 11 is supported by hollow radial arms 13 and, itself, supports the front cowling 15 by hollow radial arms 14. Cooling air is taken into the arms 13 through holes in their leading edges and passes through the annular space 41 in the wall of the chamber 11 and the hollow arms 14 to ducts 45. These ducts, of which there may be eight, lie alternately with similar but longer ducts 46 around the finned exterior of the high-pressure turbine and the ducts are open to this exterior. Air passing out of a duct 45 on to the finned exterior enters the adjacent duct 46 and passes out. therefrom, at the part which extends forwardly of the ducts 45, again on to the finned exterior and escapes into the cavity of the cowling 15. From the cavity the air escapes to atmosphere through a hole 48 at the nose and this flow of air reduces the air drag on the cowling. A fan may be provided at the hole 48 to increase the flow. The plant may be started by means of an electric motor 49 and an air-compressor within the casing 32. Specifications 585,331, 585,333 and 585,335 are referred to.